Subscribe free to our newsletters via your
. 24/7 Space News .




TIME AND SPACE
Chemical bond between a superheavy element and a carbon atom established
by Staff Writers
Mainz, Germany (SPX) Sep 23, 2014


Graphic representation of a seaborgium hexacarbonyl molecule on the silicon dioxide covered detectors of a COMPACT detector array. Image courtesy Alexander Yakushev (GSI) and Christoph E. Dullmann (JGU).

An international collaboration led by research groups from Mainz and Darmstadt has achieved the synthesis of a new class of chemical compounds for superheavy elements at the RIKEN Nishina Center for Accelerator-based Research (RNC) in Japan. For the first time, a chemical bond was established between a superheavy element - seaborgium (element 106) in the present study - and a carbon atom.

Eighteen atoms of seaborgium were converted into seaborgium hexacarbonyl complexes, which include six carbon monoxide molecules bound to the seaborgium. Its gaseous properties and adsorption to a silicon dioxide surface were studied and compared with similar compounds of neighbors of seaborgium in the same group of the periodic table.

The study recently published in Science opens perspectives for much more detailed investigations of the chemical behavior of elements at the end of the periodic table, where the influence of effects of relativity on chemical properties is most pronounced.

Chemical experiments with superheavy elements - with atomic number beyond 104 - are most challenging: First, the very element to be studied has to be artificially created using a particle accelerator.

Maximum production rates are on the order of a few atoms per day at most and are even less for the heavier ones. Second, the atoms decay quickly through radioactive processes - in the present case within about 10 seconds, adding to the experiment's complexity.

A strong motivation for such demanding studies is that the very many positively charged protons inside the atomic nuclei accelerate electrons in the atom's shells to very high velocities - about 80 percent of the speed of light.

According to Einstein's theory of relativity, the electrons become heavier than they are at rest. Consequently, their orbits may differ from those of corresponding electrons in lighter elements, where the electrons are much slower. Such effects are expected to be best seen by comparing properties of so-called homologue elements, which have a similar structure in their electronic shell and stand in the same group in the periodic table.

This way, fundamental underpinnings of the periodic table of the elements, i.e., the standard elemental ordering scheme for chemists all around the world, can be probed.

Chemical studies with superheavy elements often focus on compounds, which are gaseous already at comparatively low temperatures. This allows their rapid transport in the gas phase, benefitting a fast process as needed in light of the short lifetimes.

To date, compounds containing halogens and oxygen have often been selected; as an example, seaborgium was studied previously in a compound with two chlorine and two oxygen atoms - a very stable compound with high volatility.

However, in such compounds, all of the outermost electrons are occupied in covalent chemical bonds, which may mask relativistic effects. The search for more advanced systems, involving compounds with different bonding properties that exhibit effects of relativity more clearly, continued for many years.

In the preparation for the current work, the superheavy element chemistry groups at the Institute for Nuclear Chemistry at Johannes Gutenberg University Mainz (JGU), the Helmholtz Institute Mainz (HIM), and the GSI Helmholtz Center for Heavy Ion Research (GSI) in Darmstadt together with Swiss colleagues from the Paul Scherrer Institute, Villigen, and the University of Berne developed a new approach, which promised to allow chemical studies with single, short-lived atoms also for compounds which were less stable.

Initial tests were carried out at the TRIGA Mainz research reactor and were shown to work exceptionally well with short-lived atoms of molybdenum. The method was elaborated at Berne University and in accelerator experiments at GSI.

Dr. Alexander Yakushev from the GSI team explained: "A big challenge in such experiments is the intense accelerator beam, which destroys even moderately stable chemical compounds. To overcome this problem, we first sent tungsten, the heavier neighbor of molybdenum, through a magnetic separator and separated it from the beam. Chemical experiments were then performed behind the separator, where conditions are ideal to study also new compound classes."

The focus was on the formation of hexacarbonyl complexes.

Theoretical studies starting in the 1990s predicted these to be rather stable. Seaborgium is bound to six carbon monoxide molecules through metal-carbon bonds, in a way typical of organometallic compounds, many of which exhibit the desired electronic bond situation the superheavy element chemists were dreaming of for long.

The Superheavy Element Group at the RNC in Wako, Japan, optimized the seaborgium production in the fusion process of a neon beam (element 10) with a curium target (element 96) and isolated it in the GAs-filled Recoil Ion Separator (GARIS).

Dr. Hiromitsu Haba, team leader at RIKEN, explained: "In the conventional technique for producing superheavy elements, large amounts of byproducts often disturb the detection of single atoms of superheavy elements such as seaborgium. Using the GARIS separator, we were able at last to catch the signals of seaborgium and evaluate its production rates and decay properties. With GARIS, seaborgium became ready for next-generation chemical studies."

In 2013, the two groups teamed up, together with colleagues from Switzerland, Japan, the United States, and China, to study whether they could synthesize a superheavy element compound like seaborgium hexacarbonyl. In two weeks of round-the-clock experiments, with the German chemistry setup coupled to the Japanese GARIS separator, 18 seaborgium atoms were detected.

The gaseous properties as well as the adsorption on a silicon dioxide surface were studied and found to be similar to those of the corresponding hexacarbonyls of the homologs molybdenum and tungsten - very characteristic compounds of the group-6 elements in the periodic table - adding proof to the identity of the seaborgium hexacarbonyl. The measured properties were in agreement with theoretical calculations, in which the effects of relativity were included.

Dr. Hideto En'yo, the director of RNC, said: "This breakthrough experiment could not have succeeded without the powerful and tight collaboration between fourteen institutes around the world."

Professor Frank Maas, the director of the HIM, said: "The experiment represents a milestone in chemical studies of superheavy elements, showing that many advanced compounds are within reach of experimental investigation. The perspectives that this opens up for gaining more insight into the nature of chemical bonds, not only in superheavy elements, are fascinating."

Following this first successful step along the path to more detailed studies of the superheavy elements, the team already has plans for further studies of yet other compounds and with even heavier elements than seaborgium. Soon, Einstein may have to show the deck in his hand with which he twists the chemical properties of elements at the end of the periodic table.

.


Related Links
Johannes Gutenberg University
Understanding Time and Space






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TIME AND SPACE
Two-dimensional electron liquids
College Park MD (SPX) Sep 11, 2014
Truly two-dimensional objects are rare. Even a thin piece of paper is trillions of atoms thick. When physicists do succeed in producing 2D systems, quantum interactions can lead to new phenomena and Nobel prizes. Two examples: graphene - single-atom-thick sheets of carbon atoms - has unique mechanical, electrical, and optical properties; and two-dimensional electron gases (2DEG) - planar c ... read more


TIME AND SPACE
Year's final supermoon is a Harvest Moon

China Aims for the Moon, Plans to Bring Back Lunar Soil

Electric Sparks May Alter Evolution of Lunar Soil

China to test recoverable moon orbiter

TIME AND SPACE
NASA Mars Spacecraft Ready for Sept. 21 Orbit Insertion

India A New Contender in Asian Space Race or Technological Breakthrough

MAVEN on course for Mars Arrival Sept 21

NASA spacecraft to begin orbiting Mars within days

TIME AND SPACE
NASA Chooses American Companies to Transport US Astronauts to ISS

Space: China's final tourism frontier

NASA's Orion Spacecraft Nears Completion, Ready for Fueling

The long descent

TIME AND SPACE
Astronauts eye China's future space station

China eyes working with other nations as station plans develop

China completes construction of advanced space launch facility

China to launch second space lab in 2016: official

TIME AND SPACE
Boeing, SpaceX to send astronauts to space station

SpaceX To Deliver Science Experiments To ISS For Ames

CASIS Research Set for Launch Aboard SpaceX Mission to ISS

4th SpaceX Cargo Mission to ISS Dragon Scheduled for Sep 20

TIME AND SPACE
Elon Musk gets fresh challenge with space contract

Proton Launches May Compete on Price With US Falcons

NASA's Wind-Watching ISS-RapidScat Ready for Launch

SpaceX's next cargo launch set for Sept 20

TIME AND SPACE
Chandra Finds Planet That Makes Star Act Deceptively Old

Solar System Simulation Reveals Planetary Mystery

'Hot Jupiters' provoke their own host suns to wobble

First evidence for water ice clouds found outside solar system

TIME AND SPACE
Larry Ellison releases helm of mighty Oracle ship

Mussel-inspired MIT glue may have naval, medical applications

'Priceless' 600-tonne jade deposit found in China

NASA Awards Cross-track Infrared Sounder For JPS System-2 Bird




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.